The present invention relates to a suspension-level microactuator having an improved stroke length. More particularly, it relates to a microactuator located between a suspension and an actuator arm in a disc drive system having piezoelectric elements to selectively move a transducing head radially with respect to a rotatable disc.
The density of concentric data tracks on magnetic discs continues to increase (that is, the size of data tracks and radial spacing between data tracks are decreasing), requiring more precise radial positioning of the head. Conventionally, head positioning is accomplished by operating an actuator arm with a large-scale actuation motor, such as a voice coil motor, to radially position a head on a flexure at the end of the actuator arm. The large-scale motor lacks sufficient resolution to effectively accommodate high track-density discs. Thus, a high resolution head positioning mechanism, or microactuator, is necessary to accommodate the more densely spaced tracks.
One promising design for high resolution head positioning involves employing a high resolution microactuator in addition to the conventional low resolution actuator motor, thereby effecting head positioning through dual-stage actuation. Various microactuator designs have been considered to accomplish high resolution head positioning. However, these designs all had shortcomings that limited the effectiveness of the microactuator. Many designs increased the complexity of designing and assembling the existing components of the disc drive, while other designs were unable to achieve the force and bandwidth necessary to accommodate rapid track access. Therefore, the prior designs did not present ideal microactuator solutions. More recent microactuator designs employ piezoelectric elements to effect movement of the suspension with respect to the actuator arm. This technique has proven effective but suffers from a small range of motion.
There is a need in the art for a piezoelectric microactuator design to provide efficient high resolution head positioning in a dual-stage actuation system that allows for a greater range of motion than current designs and that can be implemented by readily available manufacturing processes.